From: Marc Zyngier <marc.zyngier@arm.com>
To: Mark Rutland <mark.rutland@arm.com>,
Andrey Konovalov <andreyknvl@google.com>
Cc: Andrey Ryabinin <aryabinin@virtuozzo.com>,
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Subject: Re: [RFC PATCH 06/14] khwasan: enable top byte ignore for the kernel
Date: Tue, 6 Mar 2018 14:24:06 +0000 [thread overview]
Message-ID: <b5f203ba-1f2f-d56e-9acf-6f269677f175@arm.com> (raw)
In-Reply-To: <20180305143625.vtrfvsbw7loxngaj@lakrids.cambridge.arm.com>
On 05/03/18 14:36, Mark Rutland wrote:
> On Fri, Mar 02, 2018 at 08:44:25PM +0100, Andrey Konovalov wrote:
>> KHWASAN uses the Top Byte Ignore feature of arm64 CPUs to store a pointer
>> tag in the top byte of each pointer. This commit enables the TCR_TBI1 bit,
>> which enables Top Byte Ignore for the kernel, when KHWASAN is used.
>> ---
>> arch/arm64/include/asm/pgtable-hwdef.h | 1 +
>> arch/arm64/mm/proc.S | 8 +++++++-
>> 2 files changed, 8 insertions(+), 1 deletion(-)
>
> Before it's safe to do this, I also think you'll need to fix up at
> least:
>
> * virt_to_phys()
>
> * access_ok()
>
> ... and potentially others which assume that bits [63:56] of kernel
> addresses are 0xff. For example, bits of the fault handling logic might
> need fixups.
Indeed. I have the ugly feeling that KVM (and anything that leaves in a
separate address space) will not be very happy with that change, as it
derives HYP VAs from the kernel VA, and doesn't expect lingering bits.
Nothing that cannot be addressed, but worth keeping in mind.
Thanks,
M.
--
Jazz is not dead. It just smells funny...
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next prev parent reply other threads:[~2018-03-06 14:24 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-02 19:44 [RFC PATCH 00/14] khwasan: kernel hardware assisted address sanitizer Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 01/14] khwasan: change kasan hooks signatures Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 02/14] khwasan: move common kasan and khwasan code to common.c Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 03/14] khwasan: add CONFIG_KASAN_CLASSIC and CONFIG_KASAN_TAGS Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 04/14] khwasan: adjust shadow size for CONFIG_KASAN_TAGS Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 05/14] khwasan: initialize shadow to 0xff Andrey Konovalov
2018-03-02 21:55 ` Evgenii Stepanov
2018-03-02 19:44 ` [RFC PATCH 06/14] khwasan: enable top byte ignore for the kernel Andrey Konovalov
2018-03-05 14:29 ` Mark Rutland
2018-03-09 18:15 ` Andrey Konovalov
2018-03-05 14:36 ` Mark Rutland
2018-03-06 14:24 ` Marc Zyngier [this message]
2018-03-09 18:21 ` Andrey Konovalov
2018-03-09 18:32 ` Marc Zyngier
2018-03-09 18:42 ` Andrey Konovalov
2018-03-09 19:06 ` Marc Zyngier
2018-03-09 19:16 ` Mark Rutland
2018-03-09 19:14 ` Mark Rutland
2018-03-09 18:17 ` Andrey Konovalov
2018-03-09 18:59 ` Mark Rutland
2018-03-02 19:44 ` [RFC PATCH 07/14] khwasan: add tag related helper functions Andrey Konovalov
2018-03-05 14:32 ` Mark Rutland
2018-03-06 18:31 ` Andrey Konovalov
2018-03-07 18:16 ` Christopher Lameter
2018-03-08 9:09 ` Dmitry Vyukov
2018-03-08 11:20 ` Mark Rutland
2018-03-02 19:44 ` [RFC PATCH 08/14] khwasan: perform untagged pointers comparison in krealloc Andrey Konovalov
2018-03-05 14:39 ` Mark Rutland
2018-03-06 18:33 ` Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 09/14] khwasan: add hooks implementation Andrey Konovalov
2018-03-05 14:44 ` Mark Rutland
2018-03-06 18:38 ` Andrey Konovalov
2018-03-08 11:25 ` Mark Rutland
2018-03-09 18:10 ` Andrey Konovalov
2018-03-13 15:05 ` Alexander Potapenko
2018-03-13 17:00 ` Andrey Konovalov
2018-03-15 16:52 ` Andrey Ryabinin
2018-03-16 18:09 ` Andrey Konovalov
2018-03-16 18:16 ` Evgenii Stepanov
2018-03-16 18:24 ` Andrey Konovalov
2018-03-16 18:45 ` Evgenii Stepanov
2018-03-16 19:06 ` Andrey Konovalov
2018-03-16 20:21 ` Evgenii Stepanov
2018-03-20 0:44 ` Anthony Yznaga
2018-03-20 13:43 ` Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 10/14] khwasan: add bug reporting routines Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 11/14] khwasan: add brk handler for inline instrumentation Andrey Konovalov
2018-03-05 14:51 ` Mark Rutland
2018-03-23 15:59 ` Andrey Konovalov
2018-03-24 3:42 ` Ard Biesheuvel
2018-03-26 9:36 ` Mark Rutland
2018-03-27 13:03 ` Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 12/14] khwasan, jbd2: add khwasan annotations Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 13/14] khwasan: update kasan documentation Andrey Konovalov
2018-03-02 19:44 ` [RFC PATCH 14/14] khwasan: default the instrumentation mode to inline Andrey Konovalov
2018-03-05 14:54 ` Mark Rutland
2018-03-09 18:06 ` Andrey Konovalov
2018-03-09 19:18 ` Mark Rutland
2018-03-12 13:10 ` Andrey Konovalov
2018-03-13 14:44 ` Alexander Potapenko
2018-03-13 16:49 ` Andrey Konovalov
2018-03-04 9:16 ` [RFC PATCH 00/14] khwasan: kernel hardware assisted address sanitizer Geert Uytterhoeven
2018-03-04 11:44 ` Ingo Molnar
2018-03-04 15:49 ` Geert Uytterhoeven
2018-03-06 18:21 ` Andrey Konovalov
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